Methods and apparatus for applying a secondary closure to an assembly of a lid attached to a battery box

ABSTRACT

An assembly  10  comprising a battery box  11  and a lid  12 . The lid  12  defines a well  13  for receiving a secondary closure  14 , with the well providing fining access to the battery box  11 . The secondary closure is applied to a battery box lid by a secondary closure applying apparatus. This comprises essentially three units: a lid and battery box assembly locating unit  16 , a heated platen unit  17  and a closure applicator  18 . By engaging lid  12 , rather tan box  11 , any offset positioning of the lid relative to the box, is substantially removed. Orientation of platen and closure  14  is made in response to the detected position of the well  13  and/or lid  12.

FIELD OF THE INVENTION

This invention relates to methods and apparatus for applying a secondaryclosure to an assembly of a lid attached to a battery box.

BACKGROUND OF THE INVENTION

For many years it has been known to manufacture sealed battery boxes byinterposing a heated platen between the top edge of a battery box andthe underneath of a lid to heat co-operating surfaces, removing theplaten and pressing the lid onto the box. This apparatus has proved tobe extremely satisfactory and there are a large number of such machinesin existing manufacturing lines throughout the world. Such batteriesusually had a plastic secondary cover or closure which could be clippedonto the lid and removed to allow topping up of the battery. More recentbattery developments have enabled manufacturers to design a completelysealed unit in which the secondary closure has to be sealed onto thelid, once the battery has been suitably filled with electrolyte.

It has now been discovered that the majority of lid fixing machines,which exist in the manufacturing lines, are not particularly accurateand small deviations in lid position relative to the battery box occur.This is not only in the lateral and longitudinal positioning of the lid,but also in its orientation.

It is perfectly possible to overcome these problems with betterengineering of the lid fixing equipment and the applicants havemanufactured a machine which consistently assembles lids with therequired accuracy. However, the investment in existing machines is suchthat this approach only provides a long term solution and currentlybattery manufacturers are rejecting a significant percentage ofbatteries because of mis-fitting secondary closures.

SUMMARY OF THE INVENTION

From one aspect the invention consists in apparatus for applying asecondary closure to an assembly of a lid attached to a battery boxincluding at least one stop or the like for locating the assembly in apredetermined position, a holder for a secondary closure, a heatableplaten interposable between and engageable with the closure and the lidto heat respective cooperable engageable surfaces thereof and a loadapplicator for engaging the heated surfaces to fix the closure to thelid characterised in that the locating stop or the like locates the lidin a predetermined position and in that the apparatus includes a platensupport for allowing the platen to move to take up the orientation ofthe engageable surface of the lid and a holder support to allow theorientation of the closure to be determined by the orientation of theplaten.

To put it another way both the platen and the closure holder are“floating” so that their orientation is determined by the orientation ofthe lid. Thus any inaccuracies in the orientation of the lid are therebyautomatically compensated. Further by locating the assembly by engagingthe lid, the position of the lid can be placed accurately longitudinallyand transversely relative to the platen. Previously the assembly hadalways been located by the position of the box.

From a further aspect the invention consists in apparatus for applying asecondary closure to an assembly of a lid attached to a battery boxincluding at least one stop or the like for locating the assembly in apredetermined position, the holder for the secondary closure, a heatableplaten interposable between and engageable with the closure and the lidto heat respective co-operable engageable surfaces thereof and a loadapplicator for engaging the heated surfaces to fix the closure to thelid characterised in that the locating stop or the like locates the lidin a predetermined position and the apparatus further includesrespective supports for each of the holder and platen for allowingrotation of the holder or platen about orthogonal axes in respectivegenerally parallel planes which are further generally parallel to thepredetermined position of the lid.

In either of these arrangements the supports may be in the form ofgimbals. The apparatus may further comprise guides for engaging the lidto guide it into a predetermined position and, in that case the stop orthe like may be mounted on the guides.

From a still further aspect the invention consists in a method ofapplying a secondary closure to an assembly of a lid attached to abattery box, the lid defining a seat for the closure, the methodincluding engaging a first face of a heated platen against the seat sothat it takes the orientation of the seat, engaging the closure againstthe opposite face of the platen so that it takes the orientation of theplaten, removing the platen and engaging the orientated closure againstthe seat.

From a still further aspect the invention consists of apparatus forlocating a secondary closure on the lid of a battery box including atleast one detector for detecting the position and/or orientation of thelid or a part thereof and a closure applicator responsive to thedetector for adjusting the orientation and/or position of the closureprior to application, in accordance with the detectedposition/orientation.

From yet another aspect, the invention consists in apparatus forapplying a secondary closure to an assembly of a lid attached to abattery box including at least one stop or the like for locating theassembly in a predetermined position, a holder for a secondary closure,a heatable platen interposible between and engageable with the secondaryclosure and the lid to heat respective co-operable engageable surfacesthereof and a load applicator to engaging the heated surfaces to fix thesecondary closure to the lid, characterized in that the locating stop orthe like comprises a seat for the battery box lid positionable betweenthe heatable platen and the battery box and in that the apparatus alsoincludes a battery box support for allowing the battery box to move sothat the battery box lid takes up the orientation of an engageablesurface of the battery box lid seat.

Although the invention has been defined above it is to be understood itincludes any inventive combination of the features set out above or inthe following description.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention may be performed in various ways and specific embodimentswill now be described, by way of example, with reference to theaccompanying drawings, in which:

FIG. 1 is a side view of a lid and battery box assembly with a secondaryclosure positioned above it;

FIG. 2 is an end view of FIG. 1;

FIG. 3 a is a view from above of the secondary closure and FIG. 3 b is aview from above of the lid and battery box assembly;

FIG. 4 is a schematic side view of the apparatus of the invention withthe platen holder partly in section with a closure and lid and batterybox assembly located therein;

FIG. 5 is a plan view of a closure holder on the arrow A;

FIG. 6 is a plan view on the arrow B of the platen and its holder; and

FIG. 7 is a schematic view of the apparatus of a second aspect of theinvention showing a battery box on a floating support.

DETAILED DESCRIPTION OF THE DRAWINGS

As can be seen in FIGS. 1 to 3 an assembly 10 comprises a battery box 11and a lid 12. The lid 12 defines a well 13 for receiving a secondaryclosure 14 the well provides filling access to the battery box 11, aspreviously described.

Turning to FIG. 4 a secondary closure applying apparatus isschematically and generally indicated at 15. This comprises essentiallythree units: a lid and battery box assembly locating unit 16, a heatedplaten unit 17 and a closure applicator 18.

The unit 16 comprises a support 19 onto which the pre-formed lid andbattery box assembly 10 is delivered by a conveyor (not shown) and aguide and stop assembly 20. The guide and stop assembly 20 includesguides 21 which engage the lid 12 as it is moved onto the support 19 tolocate laterally the lid 12 in a predetermined, position. Mounted on oneof the guides 21 is an end stop 22, which also engages the lid 12, andlocates the battery box longitudinally in its predetermined position.The support 19 is mounted on a ram 23 which enables the battery box tobe raised and lowered. The stop 22 can be swung out of the way on itspivot 24 when the closure applying process is complete.

The platen unit 17 comprises a carriage 25 that can be moved laterally,as indicated by the arrows, by means of a gear wheel 26, which is drivenby a motor (not shown). Mounted on the carriage is a gimbal 27 thatsupports a heatable platen 28. The gimbal 27 allows the platen to rotateabout the horizontal axes defined by the pairs of stub axials 29 and 30.

The closure applicator includes a closure holder 31 which is mounted ina gimbal 32 on a head 33. The head 33 is in turn carried by a ram 34, sothat the head 33 can be moved vertically as indicated by the arrows.

The closure support 31 has orifices 35 which are connected to a vacuumsource (not shown) so that the closure 12 can be releasably heldthereon, as shown in FIG. 4.

In use, the assembly 10 is delivered onto the support 19 by the conveyor(not shown) and, as it moves onto the support 19, the lid 12 is engagedby guides 21 and subsequently by a stop 22 so that the assembly 10 isheld both laterally and longitudinally in a predetermined position. Thusas has been mentioned before, by engaging the lid 12 rather than the box11, any longitudinal or lateral offset of the lid 12 with respect to thebox 11 is effectively taken out of the equation. Commonly the secondaryclosures will arrive loosely fitted on the main lid in which case theywill need to be picked up initially by the head 33 prior to theinsertion of the platen 28 above the box. Alternatively the secondaryclosures can be provided directly to the head 33, from a cassette or thelike.

The carriage 25 is then driven by a gear 26 so that it is interposedbetween the well 13 and the closure 14. A ram 23 is then activated topress the well against the platen 28 and, because the platen 28 ismounted in the gimbal 27, the platen takes up the orientation of thewell 13. A ram 34 is then activated bringing the closure 14 against theother face of the platen 28 and the closure 14 can then take up theorientation of the platen 28 because it in turn is effectively mountedon the gimbal 32. As soon as appropriate heating has taken place the lidand the box are retracted and the gear 26 withdraws the carriage 25 andplaten 28 and the orientated closure 14 is pressed against the seatsformed in the well 13 to seal it therein.

It will be appreciated that rams 23 and 34 could be activatedsimultaneously, but because of the lower thermal capacity of the closure14 there is some benefit in allowing the platen 28 to engage the well 13first. It may alternatively be desirable to provide a thermal breakwithin the platen, although that could cause some difficulties withplaten manufacture due to thermal stresses. It will be appreciated thatthe gimbal 32 needs to be sufficiently stiff to maintain the position ofthe closure 14 once it has been orientated by the platen 28, butalternatively means could be provided for releasably locking the gimbalonce the platen has been engaged.

In FIG. 7, we see substantially the same apparatus as in FIG. 4, with alid and battery box assembly locating unit 16, a heated platen unit 17and a closure applicator 18. In this case, the apparatus includes abattery box lid seat 36 associated with stop 22. This seat is a fixedunit which positions the battery box lid when it is brought intoengagement with the seat. The battery box sits on a battery support 19a. The battery support 19 a is allowed to float due to the use ofsprings 38 and a spherical bearing 37. It is envisaged that other meansof providing a floating support can be used, for example, using gimbalarrangements rather than springs and spherical bearings. What isimportant is that support 19 a can more relative to the lid seat 36.Again, by engaging the lid 12, rather than box 11, any offsetpositioning of the lid 12 relative to the box 11, is substantiallyremoved.

When using the apparatus, the lid pick up arrangement 18 secures asecondary closure. The battery box support 19 is brought into contactwith the lid seat by ram 23. The springs 38 and bearing 37 allow thebattery box lid to be positioned in the seat so that it will align withplaten 17. The closure applicator 18 is brought into contact with platen18 as the seat and lid are brought into contact and melting of theclosure occurs which allows it to seal onto the assembly of a lidattached to the battery box.

It will be appreciated that as the platen and closure positions aredetermined on a box-by-box basis each closure should be accuratelylocated, whatever the errors in orientation that have been createdduring the previous manufacturing step. It will also be appreciated,that the floating mounting of the platen 28 and closure 14 could besubstituted by a positively driven arrangement which orientated theplaten and closure in response to the detected position of the well 13and/or of the lid 12. Such an arrangement is included within theinvention, but in most circumstances it will be regarded as undesirablyexpensive. The detection could take place using probes to ascertain thelocation of the corners of the lid 12 or the well 13. These signalswould allow computation of location signals which would be used toadjust the position and/or orientation of the platen and the lid holder.As the same degrees of freedom are required for both the driven and‘floating’ approaches the ‘floating’ version is preferred except wherethere are difficulties in maintaining lid orientation.

1. Apparatus for applying a secondary closure to an assembly of a liddefining a seat for the secondary closure and attached to a battery boxincluding at least one locating stop for locating the assembly in apredetermined position, a holder for the secondary closure, a heatableplaten interposable between and engageable with the secondary closureand the lid to heat respective co-operably engageable surfaces thereofand a load applicator for engaging the heated surfaces to fix thesecondary closure to the seat of the lid; wherein the locating stoplocates the lid in a predetermined position and the apparatus includes aplaten support for allowing the platen to move to take up theorientation of the engageable surface of the lid and a holder support toallow the orientation of the secondary closure to be determined by theorientation of the platen.
 2. The apparatus according to claim 1,wherein at least one of the supports is a gimbal.
 3. The apparatusaccording to claim 1, further comprising guides for engaging the lid toguide it into the predetermined position.
 4. The apparatus according toclaim 1, wherein the stop is mounted on guides.
 5. Apparatus forapplying a secondary closure to an assembly of a lid defining a seat forthe secondary closure and attached to a battery box including at leastone locating stop for locating the assembly in a predetermined position,a holder for the secondary closure, a heatable platen interposablebetween and engageable with the secondary closure and the lid to heatrespective co-operably engageable surfaces thereof and a load applicatorfor engaging the heated surfaces to fix the secondary closure to theseat of the lid; wherein the locating stop locates the lid in apredetermined position and the apparatus further includes respectivesupports for each of the holder and platen for allowing rotation of theholder or platen about orthogonal axes lying in respective generallyparallel planes which are further generally parallel to thepredetermined position of the lid.
 6. The apparatus according to claim5, wherein at least one of the supports is a gimbal.
 7. The apparatusaccording to claim 5, further comprising guides for engaging the lid toguide it into the predetermined position.
 8. The apparatus according toclaim 5, wherein the stop is mounted on guides.
 9. A method of applyinga secondary closure to an assembly of a lid attached to a battery box,the lid defining a seat for the secondary closure, the methodcomprising: engaging a post face of a heated platen against the seat sothat it takes the orientation of the seat; engaging the secondaryclosure against the opposite face of the platen so that it takes theorientation of the platen; removing the platen; and engaging theoriented secondary closure against the seat.
 10. Apparatus for locatinga secondary closure on the lid of a battery box including at least onedetector for detecting the position and/or orientation of the lid or apart thereof and a closure applicator responsive to the detector foradjusting the orientation and/or position of the secondary closure priorto application, as a function of the detected position/orientation. 11.Apparatus for locating a secondary closure to an assembly of a lidattached to a battery box including at least one locating stop forlocating the assembly in a predetermined position, a holder for asecondary closure, a heatable platen interposable between and engageablewith the secondary closure and the lid to heat respective co-operablyengageable surfaces thereof and a load applicator for engaging theheated surfaces to fix the secondary closure to the lid; wherein thelocating stop comprises a seat for the battery box lid positionablebetween the heatable platen and the battery box, and the apparatus alsoincludes a battery box support for allowing the battery box to move sothat the battery box lid takes up the orientation of an engageablesurface of the battery box lid seat; the battery box support beingmovable by a self adjusting mechanism.
 12. The apparatus for locating asecondary closure according to claim 11, wherein the self adjustingmechanism comprises springs and spherical bearing arrangement.
 13. Theapparatus for locating a secondary closure according to claim 12,wherein the self adjusting mechanism includes one or more gimbals. 14.The apparatus for locating a secondary closure according to claim 11,wherein the self adjusting mechanism includes one or more gimbals.